Featured Research

from universities, journals, and other organizations

White Blood Cells In Lung Produce Histamine Seen In Allergies

Date:

January 12, 2007

Source:

University of California - San Francisco

Summary:

In a surprise finding, scientists have discovered that histamine, the inflammatory compound released during allergic reactions that causes runny nose, watery eyes and wheezing, can be produced in large amounts in the lung by neutrophils, the white blood cells that are the major component of pus.

Share This

In a surprise finding, scientists have discovered that histamine, the inflammatory compound released during allergic reactions that causes runny nose, watery eyes, and wheezing, can be produced in large amounts in the lung by neutrophils, the white blood cells that are the major component of pus.

Related Articles

Pus, a fluid found in infected tissue, is produced as a result of inflammation.

The study in mice is the first to show that lung neutrophils can produce histamine in significant quantities, according to principal investigator George Caughey, MD, chief of pulmonary/critical care medicine at the San Francisco VA Medical Center.

"Previously it was thought that the primary sources of lung histamine, in health as well as disease, was mast cells, which are classically associated with allergy," notes Caughey, who is also a professor of medicine at the University of California, San Francisco.

Caughey says the result could mean that histamine acts as a link between airway infections and asthma and bronchitis, which are associated with allergy. "In both, we observe inflammation ---- swelling, blood vessel leak, and muscle contraction that narrows the airway."

The study appears in the January 2007 issue of the Journal of Experimental Medicine.

Caughey was investigating the well-known fact that upper respiratory infections often trigger acute asthma attacks. "We hypothesized that an infection in the airway would release histamine from mast cells, and that would be one of the reasons," he explains.

To test the hypothesis, Caughey and his team exposed two different populations of mice to mycoplasma, a common respiratory infection in rodents and humans. One population had a genetic abnormality that causes a total lack of mast cells; the other population was made up of normal, wild-type mice. Both populations of infected mice developed pneumonia.

"We thought the mice without mast cells would do better than the wild-type mice, because the infection wouldn't be provoking mast cells to release histamine," recalls Caughey. "In fact, they did much worse. Even though there were no mast cells, histamine levels rose up to 50 times normal."

The reason was straightforward, Caughey says. Neutrophil numbers increased in response to infection, and neutrophils in turn produced histamine. "It's a direct effect of the mycoplasma bacteria on neutrophils. They induce neutrophils to produce the enzyme that produces histamine."

Individual neutrophils produce much less histamine than individual mast cells, says Caughey, but "because pus contains millions if not billions of neutrophils, the overall amount they make is very considerable."

The neutrophil-histamine effect was similar in the wild-type mice, reports Caughey: "Histamine levels from neutrophils blew right past the histamine levels contributed by mast cells."

The wild-type mice suffered less severe infections overall because "as a number of recent studies, including ours, have shown, mast cells actually play a role in protecting against bacteria," Caughey explains. "For example, a mouse without mast cells with the equivalent of a ruptured appendix will die of the resulting infection, while a mouse with mast cells can survive."

When the infected mice without mast cells were given antihistamines, the level of histamine, and therefore the severity of the pneumonia, dropped in proportion to the amount of antihistamine given.

"This is a study in mice, so we cannot freely extrapolate the results to human beings," cautions Caughey. "Nonetheless, antihistamines may deserve more of a look as therapeutic options in lung and airway infection."

He says the study also has implications for other types of airway infection "in which there are a lot of white blood cells ---- cystic fibrosis, for example, which can be associated with asthma-like airway contraction."

The next steps for Caughey and his research team are to investigate "how general this result might be. Does only one type of bacteria cause the effect, or do others, also? Is it limited to rodents, or does it carry forward to humans? And if it does, is the amount of histamine produced by neutrophils enough to make a clinical difference?"

The study was supported by funds from the National Institutes of Health, the Diamond Family Foundation, and an Elizabeth Nash memorial fellowship from Cystic Fibrosis Research, Inc. A part of the NIH funds was administered by the Northern California Institute for Research and Education.

University of California - San Francisco. "White Blood Cells In Lung Produce Histamine Seen In Allergies." ScienceDaily. ScienceDaily, 12 January 2007. <www.sciencedaily.com/releases/2007/01/070112122920.htm>.

University of California - San Francisco. (2007, January 12). White Blood Cells In Lung Produce Histamine Seen In Allergies. ScienceDaily. Retrieved March 3, 2015 from www.sciencedaily.com/releases/2007/01/070112122920.htm

University of California - San Francisco. "White Blood Cells In Lung Produce Histamine Seen In Allergies." ScienceDaily. www.sciencedaily.com/releases/2007/01/070112122920.htm (accessed March 3, 2015).

More From ScienceDaily

More Health & Medicine News

Featured Research

Mar. 3, 2015 — Adults over the age of 30 only catch flu about twice a decade, a new study suggests. So, while it may feel like more, flu-like illness can be caused by many pathogens, making it difficult to assess ... full story

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight or treat type 2 diabetes. While the surgeries have been linked to a decreased ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Mar. 3, 2015 — Twice as many children born to mothers who took antibiotics during pregnancy were diagnosed with asthma by age 3 than children born to mothers who didn’t take prenatal antibiotics, a new study has ... full story

Mar. 3, 2015 — Pediatric otolaryngologists and surgeons are concerned with parents getting the wrong message regarding the safety/desirability of letting babies and young children eat peanuts to prevent them from ... full story

Featured Videos

Mom Triumphs Over Tragedy, Helps Other Families

AP (Mar. 3, 2015) — After her son, Dax, died from a rare form of leukemia, Julie Locke decided to give back to the doctors at St. Jude Children&apos;s Research Hospital who tried to save his life. She raised $1.6M to help other patients and their families. (March 3)
Video provided by AP

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Woman Convicted of Poisoning Son

AP (Mar. 3, 2015) — A woman who blogged for years about her son&apos;s constant health woes was convicted Monday of poisoning him to death by force-feeding heavy concentrations of sodium through his stomach tube. (March 3)
Video provided by AP

Related Stories

June 10, 2014 — Summer allergies can cause severe symptoms for some sufferers, and can be just as bad as the spring and fall seasons. Some unusual symptoms can leave you looking like you lost a round in a boxing ... full story

Mar. 10, 2014 — This winter has been one of the coldest on record, but spring allergy season is already beginning and it’s time for sufferers to start preparing now. An estimated 50 million Americans suffer from ... full story

Nov. 1, 2012 — Researchers have discovered a novel target for the treatment of food allergies. Levels of the enzyme Pim 1 kinase rise in the small intestines of peanut-allergic mice. Inhibiting activity of Pim 1 ... full story

Jan. 31, 2012 — Could some cases of asthma actually be caused by an allergic reaction to a common environmental bacteria? New research findings suggests that this idea may not be as far-fetched as it ... full story

Jan. 31, 2011 — If you think histamines are your nemesis during allergy season, here's something that might change your perspective. New research shows that histamine could be an important molecule to ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.